Move ringing status indicator to header on mobile

On mobile, the ringing status indicator is supposed to display in the header rather than on a tile. The exact layout differs between Android and iOS. To get it right I had to refactor AppBar to use CSS grid templates.

(Also, I changed my mind about the exact ringing data I needed out of CallViewModel - sorry. A little move of the ringtone audio renderer into its own component was necessary to accommodate that.)

src/room/RingingAudioRenderer.tsx

@@ -0,0 +1,72 @@
+/*
+Copyright 2026 Element Creations Ltd.
+
+SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+Please see LICENSE in the repository root for full details.
+*/
+
+import { useEffect, type FC } from "react";
+import { logger } from "matrix-js-sdk/lib/logger";
+
+import { type RingingMediaViewModel } from "../state/media/RingingMediaViewModel";
+import { useBehavior } from "../useBehavior";
+import { useInitial } from "../useInitial";
+import { prefetchSounds } from "../soundUtils";
+import ringtoneMp3 from "../sound/ringtone.mp3?url";
+import ringtoneOgg from "../sound/ringtone.ogg?url";
+import { type UseAudioContext, useAudioContext } from "../useAudioContext";
+import { useLatest } from "../useLatest";
+
+interface RingingAudioRendererProps {
+  vm: RingingMediaViewModel | null;
+  muted: boolean;
+}
+
+export const RingingAudioRenderer: FC<RingingAudioRendererProps> = ({
+  vm,
+  muted,
+}) => {
+  // Preload a waiting and decline sounds
+  const sounds = useInitial(async () => {
+    return prefetchSounds({
+      ringtone: { mp3: ringtoneMp3, ogg: ringtoneOgg },
+    });
+  });
+  const audio = useAudioContext({
+    sounds,
+    latencyHint: "interactive",
+    muted,
+  });
+
+  return vm && <ActiveRingingAudioRenderer vm={vm} audio={audio} />;
+};
+
+interface ActiveRingingAudioRendererProps {
+  vm: RingingMediaViewModel;
+  audio: UseAudioContext<"ringtone"> | null;
+}
+
+const ActiveRingingAudioRenderer: FC<ActiveRingingAudioRendererProps> = ({
+  vm,
+  audio,
+}) => {
+  const audio_ = useLatest(audio);
+  const pickupState = useBehavior(vm.pickupState$);
+
+  // While ringing, loop the ringtone
+  useEffect((): void | (() => void) => {
+    if (pickupState === "ringing" && audio_.current) {
+      const endSound = audio_.current.playSoundLooping(
+        "ringtone",
+        audio_.current.soundDuration["ringtone"] ?? 1,
+      );
+      return () => {
+        void endSound().catch((e) => {
+          logger.error("Failed to stop ringing sound", e);
+        });
+      };
+    }
+  }, [pickupState, audio_]);
+
+  return null;
+};